Gauge acting up

Here it is 1992 Bronco XLT, 5.8L, E40D, 180,000 miles. Everything work fine except for the fuel gauge. It started moving up and down the scale even though the tank is full. Settled out at 1/4 of a tank then moves up and down
. Just started after a heavy rain. (Bad Ground?) Also seems to be affecting the oil pressure gauge it swung once and then worked fine after shut down and restart. I have a complete set of wiring diagrams for the truck and there are a lot of grounds to check.Has anyone ever seen this or has a idea on which grounds to look at first??
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Try the instrument voltage regulator (IVR) that limits instrument input voltage to 5 volts. These go bad and create strange readings.
Mbflash wrote:

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On my 92 F-250, it was the gauge itself
--
Stephen W. Hansen
ASE Certified Auto Technician
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Both gauges are magnetite, not the old style by-metal spring, no IVR.

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You have one gound to check on the fuel guage. The oil guage is on another circuit, one will not affect the other.

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See: http://www.ford-trucks.com/forums/archive/index.php/t-38429
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Articles for pre 92 vehicles. E series vans were the last to use the by-metal gauge, that was until 92, the 92 model year changed to magnetic 12 volt gauges. F series trucks by model year 87 had magnetic 12 volt gauges. Just because some web site says it is so, does not mean it is.

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